On the Angular Distribution of ⁸Li in ⁹Be(π⁻, πN)⁸Li at P_beam=1.0, 3.0, and 4.0 GeV/c

Abstract

Angular distributions of recoil ⁸Li in the ⁹Be(π⁻, πN)⁸Li reaction have been measured at P_beam(π⁻)=1.0, 3.0, and 4.0 GeV/c with solid state track detector (SSTD). At 1.0 and 3.0 GeV/c, the heavy-fragment knockout process explains the major feature of the data, whereas at 4.0 GeV/c a characteristic sideways peaking is observed at around θ_1ab\simeq30°. The latter phenomenon shows that another effects must begin to occur at around 4.0 GeV/c. The ¹²C, ¹⁴N, ¹⁶O→⁸Li, ⁸B spallation reactions by π⁻ mesons (background reactions) have also been measured. They are mainly due to the intra-nuclear cascade and evaporation process.